Old-time monarchies and modern dictators govern by decree. Not so in the United States, where the Constitution does not give the president such power.
So it is fair to wonder what authorized President Barack Obama to "suspend" the portion of the Affordable Care Act that imposes a health-care mandate on employers.
There are times when the president can issue decrees that have the force of law. For example, Congress may legislate that certain things will or will not happen unless the president issues certain findings.
In 1936, the Supreme Court upheld a law passed in 1934 that made it a crime to sell munitions to Bolivia, which was engaged in an armed conflict, if the president made certain findings.
The Constitution also gives the president specific unilateral powers, such as the power to decide which foreign countries to recognize and the authority to grant pardons.
The president can refuse to prosecute someone criminally because the Constitution gives the executive branch absolute prosecutorial discretion. That is how Obama justified not enforcing deportation laws in certain circumstances.
The president also need not enforce a law that he believes is unconstitutional. Sound precedent justifies this power.
The Justice Department's Office of Legal Counsel is, in effect, the lawyer for the government.
It issues legal opinions that courts often rely on. It advises that the president may refuse to enforce a law he thinks is unconstitutional.
It derived this power from two clauses of the Constitution: One requires the president to "take Care that the Laws be faithfully executed." The other requires him to "preserve, protect and defend the Constitution of the United States."
The OLC agreed with Chief Justice Salmon P. Chase, who wrote in 1868 that the president's obligation to defend the Constitution authorizes him to decline to enforce statutes that he believes violate it.
The OLC has also concluded that the president could refuse to enforce a law before the judiciary decides whether it is constitutional.
Thus, before the Supreme Court ruled on the issue last month, Obama acted properly in legally ordering the Justice Department not to defend a federal law he considered unconstitutional because it did not recognize same-sex marriage.
The president does not, however, have carte blanche to refuse to enforce the law. "Obviously," the OLC wrote in 1990, the president cannot "refuse to enforce a statute he opposes for policy reasons."
In 1838, the Supreme Court advised: "To contend that the obligation imposed on the President to see the laws faithfully executed implies a power to forbid their execution is a novel construction of the constitution and entirely inadmissible."